ABSTRACT The present research advances the science of sexual assault prevention research by rigorously evaluating two theoretically-driven, multi-session sexual assault prevention programs for high school boys with different administration approaches: (1) Your Voice Your View, developed and currently administered in Rhode Island high schools by the CDC RPE-funded agency Day One of Rhode Island; and (2) The High School Workshop, adapted from the Men's Workshop, which was previously evaluated among college men by members of this research team. Our approach to this efficacy research is not only rigorous, but also novel; exemplifying how mutually beneficial partnerships between well-established researchers and community agencies advance the science of sexual assault prevention by enhancing the capacity of community agencies to conduct rigorous program evaluations and enriching the ability of researchers to develop interventions that are sustainable outside of a laboratory setting. In the Refinement and Planning Phase, we will refine the program manuals through informant interviews, focus groups, stakeholder interviews, establishment of a Research Advisory Board, and administration of a small open pilot trial. An online survey will also be conducted to gather social norms data, and The High School Workshop will be adapted to be feasible and sustainable in a high school setting. In order to consistently administer Your Voice Your View in the context of this research design, the program will be further manualized, training manuals will be produced, and measures assessing the fidelity of program administration (i.e., adherence/competence measures) will be developed. In the Intervention Phase, we will conduct a randomized controlled trial with a sample of 1200 10th grade boys to demonstrate efficacy of each intervention in reducing rates of sexual aggression, dating violence involvement, and related risk/protective factors over a 6-month follow-up relative to a dose- and attention-matched General Health Promotion control group. At least six schools will be matched on demographic characteristics (i.e., % receiving subsidized lunch, racial/ethnic minority enrollment) then randomized to receive Your Voice Your View (N = 400), the High School Workshop (N = 400), or General Health Promotion (N = 400). In the Analysis and Dissemination Phase, we will conduct additional stakeholder interviews (N = 12), analyze study data, conduct cost-effectiveness analyses, prepare project reports, and share study findings with the schools as well as the local and national scientific communities. By addressing the weaknesses of both the community-based prevention program (i.e., lacking rigorous evaluation) and the research-based prevention program (i.e., lacking real-world applicability), testing both programs in comparison to a dose-and attention-matched control group, and conducting a preliminary examination of the differential efficacy of the two interventions, the results of this research will make a significant contribution to the evidence base for preventing sexual aggression among high school boys. The knowledge, infrastructure and experience provided to the community agency and research team as a result of conducting the present research will also enhance the capacities of both parties to more effectively integrate research and practice in future sexual assault prevention work.